Answer:
a that all you need and why you just and use a calculators and what they are for
a) To find the mass after t years:we will use this formula:
A = Ao / 2^n when A =the amount remaining
and Ao = the initial amount
and n = t / t(1/2)
by substitution:
∴ A = 200 mg/ 2^(t/30y)b) Mass after 90 y :by using the previous formula and substitute t by 90 y
A = 200mg/ 2^(90y/30y)
∴ A = 25 mgC) Time for 1 mg remaining:when A= Ao/ 2^(t/t(1/2)
so, by substitution:
1 mg = 200 mg / 2^(t/30y)
∴2^(t/30y) = 200 mg by solving for t
∴ t = 229 y
Answer:
The TV signal.
Explanation: Hope this is right! :)
Answer:
pH = 6.8124
Explanation:
We know pH decreases with increase in temperature.
At room temperature i.e. 25⁰c pH of pure water is equal to 7
We know
Kw = [H⁺][OH⁻]...............(1)
where Kw = water dissociation constant
At equilibrium [H⁺] = [OH⁻]
So at 37⁰c i.e body temperature Kw = 2.4 × 10⁻¹⁴
From equation (1)
[H⁺]² = 2.4 × 10⁻¹⁴
[H⁺] = √2.4 × 10⁻¹⁴
[H⁺] = 1.54 × 10⁻⁷
pH = - log[H⁺]
= - log{1.54 × 10⁻⁷}
= 6.812
I think what '13C' means is the isotope of carbon with mass number of 13. Its mass is 13 amu. The unit amu is equivalent to g/mol. The average atomic mass of Carbon is actually 12. But since we are solving for this particular isotope, we use a molar mass of 13 g/mol.
2 g C-13 * 1 mol/13 g = 0.154 moles of C-13